A conventional treadmill shown in FIG. 9 generally includes a base 80, a frame 81 that has one pivotal end connected to the base and an endless running belt 82 is mounted to the frame. The endless running belt can also be driven by a motor so that the users can set desired running speed to exercise.
Some conventional treadmills are equipped with incline adjusting mechanisms, which link driving devices on the frames. The driving device drives the end of the frame up and down to reach the purpose of adjusting the inclination of the frame. But the incline adjusting mechanism can only adjust the inclination of the frame and unable to fold the frame.
In order to save space occupied by the treadmill, some treadmills are equipped with folding devices shown in FIG. 9, which allow the frame to be pivotally related to the base. U.S. Pat. No. 6,527,679 discloses a folding mechanism, which uses a motor and a threaded rod that is driven by the motor and a connection member pivotally connected to the frame is movably mounted to the threaded rod so that when the threaded rod is rotated by the motor, the connection member pivots the frame. It is noted that the folding mechanism can only fold the frame but unable to adjust the inclination of the frame.